Gration is a moon that orbits the planet Tonus. It is mostly covered by fresh ice and is the most reflective body in the system. Consequently, temperatures only reach −198 °C, far colder than a light-absorbing body would be. It has a wide range of surface features, ranging from old, heavily cratered regions to young, tectonically deformed terrains. It has a thin Type IV atmosphere and is not capable of supporting life.